Centralized traffic control system for railroads



Jan. 2 5, 3933a R. M. PHINNEY 1,895,422

CENTRALIZED TRAFFIC CONTROL SYSTEM FOR RAILROADS 3 Sheets-Sheet 1 Filed on. 1, 1930 R m9 N E V mm "Md/um Wm (M O fig MN Ill... no w n L. 0 G m m- Si 216 n 1 ATTORNEY Jan. 24, 1933. R. M. PHINNEY 193959422 CENTRALIZED TRAFFIC CONTROL SYSTEM FOR RAILROADS Filed Oct. 1, 1952 3 Sheets-Sheet 2 BY @W Q W J) ATTORNEY Jan. 24, 1933. R. M. PHlNNEY CENTRALIZED TRAFFIC CONTROL SYSTEM FOR RAILROADS Filed Oct. l, 1930 3 Sheets-Sheet 3 FIGO5,

Patented Jan. 24, 1933 UNITED STATES PATENT OFFICE ROBERT M. PHINNEY, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK CENTRALIZED TRAFFIC CONTROL SYSTEM FOR RAILROADS Application filed October 1, 1980. Serial No. 485,579.

This invention relates to systems for governing or regulating traiiic on railroads, and more particularly to a system of train dispatching or centralized traflic control for railroads.

In a system of the type generally known as a train dispatching or centralized trafiic control system, the power operation of track switches at the ends of passing sidings and like locations is under the control of an operator or dispatcher located at some convenient control office; and by causing these track switches to assume the desired position, and by controlling the indications of signals governing train movements over these switches and through the connecting portions of track, the operator is able to direct or regulate train movements by signal indications with safety and facility, and without the use of written train orders.

In accordance with this invention, it is proposed to employ, instead of a poweroperated switch at the ends of passing sidings and at similar locations, what is commonly known as a spring switch. A spring switch,

as commonly used, is one in which the switch points are held in one extreme position, usually the normal position, by a heavy spring; and this spring acts to return the switch points automatically to this normal position after they have been displaced by a train trailing the switch, a suitable dashpot device being usually employed to retard the return movement of the switch points, so that they are not shifted back and forth by the wheels of a train trailing the switch. Since the spring mechanism, which may break or get out of order is all that holds the switch points in the normal position, it is generally considered that train movements over a spring switch in the facing direction should be made at slow speeds.

One object of this invention is to provide suitable manually releasable locking means of the plunger type for positively holding the switch points of a spring switch in the normal position, so that trains may safely pass over the switch in the facing direction at the normal running speeds, and to provide a system of signal indications and control circuits such that the distant operator is able to direct train movements over the switch as desired, and with the necessary protection to the trains, the switch points being shifted to the reverse position as required by the usual hand-throw device or switch stand.

Other objects, characteristic features, advantages, and the principles and mode of operation of the invention will be in part apparent, and in part pointed out in the following explanation of the structure and mode of operation of certain specific embodiments of the invention.

In the accompanying drawings, Fig. 1 shows in a simplified and diagrammatic manner, with certain conventional illustrations, one embodiment of the invention applied to a spring switch at one end of a passing siding, the parts and circuits being shown more for the purpose of making it easier to understand the nature of the invention, than with the idea of illustrating specifically the particular arrangement and structure of parts and circuits preferably employed in practice; Figs. 2 and 3 are fragmentary views showing the switch lock of Fig. l in different positions; and Figs. 4, 5 and 6 illustrate modifications of control circuits for the lock magnet.

Referring to the accompanying drawings, the switch SE, to which the invention has been shown applied, is located at one (west) end of a passing siding PS for a single track railroad; and it is assumed that this railroad is equipped with a block signaling system of the absolutepermissive-block type, such as disclosed, for example, in the patent to S. N. Y Vight, No; 1,294,736, dated February 18, 1919. Only some of the signal control circuits more directly related to this invention havebeenillustrated; and reference may be made to said Wight patent for a more complete disclosure of the signaling system, with which the improved system of this invention is used.

- The main track is divided by insulated joints into track circuit sections in the usual way, one such track circuit section 4, with the adjoining ends of the two adjacent track sections 3 and 5 having been shown. Each of these track sections is provided with the usual track battery, such as the battery 6, and a track relay. The track relays are shown conventionally by dotted lines, and are designated 3T, etT, and 5T. The track section 4 at the switch SWV extends back to the fouling point on the siding, and the switch leads and track rails are cross-bonded in some suitable way (not shown), in accordance with established practice, to provide the usual detector track circuit.

A home signal 1 governs east-bound trafiic (left to right) toward the siding PS; and associated with this signal, and preferably located 011 the same pole, is a take-siding signal ITS, which gives a distinctive indication distinguishable from the indications of the block signals. This take-siding signal may be any one of the well-known and accepted types.

The leaving or starting signal 2, which governs west-bound traflic on the main track, and which is an absolute or stop-and-stay signal, in accordance with the common practice in an absolute-permissive-block signal system, is preferably located in accordance with this invention at the point indicated, opposite the fouling point for the siding and at the end of the detector track section 1. Associated with this starting signal 2 is a leavesiding signal 2LS, which may be located on the same pole and have a distinctive aspect, but which is preferably located at the siding, as shown, and constructed to give the usual indications of an absolute low speed or dwarf signal.

A leave-siding indicator LSI, shown conventionally, is preferably employed to enable the distant operator to indicate to the crew of a train standing on the siding when the switch SWV should be unlocked and reversed for this train to come out of the siding. This indicator LS1 may be a simple pot signal, or the like, and is preferably located near the fouling point where it can be easily seen by the engineer or trainman. The use of this indicator is optional; and if desired, instructions to the train crew to unlock and reverse the switch SW and leave the siding may be communicated over the telephone, as explained hereinafter.

The signals 1 and 2, shown as semaphore signals, may be color-light signals, or of any other suitable type. The signal 1 is controlled by a line relav 1H and a remotely controlled relay lG. To simplify the illustration, only the controls for two indications of these signals have been indicated by dotted lines; but it should be understood that in practice the line relays 1H and 2H are neutral-polar relays, and are controlled over polarized line circuits so as to provide, in conjunction with the relays 1G and 2G, the usual three distinctive indications of proceed, caution, and stop. The line or control circuit for the linerelay 1H has only been partially shown as including front contacts of the track relays 4T and 5T in advance of this signal, and other controlling contacts designated conventionally at 8. Similarly, the line circuit for the line relay 2H includes front contacts of the track relays 4T and 3T in advance thereof (considering the direction of travel controlled by the signal 2) and other controlling contacts designated conventionally at 9. The control of these line relays 1H and 2H by the detector track relay 4J1 may be omitted, if desired, and the relays 1G and 2G be controlled bythis detector track relay. In accordance-with recognized prac tice in dispatching or centralized traffic control systems, the home signal 1 is preferably electrically interlocked with the corresponding home signal at the other end of the siding, as shown and described, for example, in the application of S. N. Wight, Ser. No. 120,423, filed July 3, 1926, which also shows other features of the signal circuits preferably employed in connection with this inven tion.

The take-siding signal ITS is cleared or caused to give its distinctive indication when a relay lTSG is energized; and the leave-siding signal 2LS is similarly controlled by relay 2LSG.

The switch SlV is of the usual construction, with a front rod 7, to which is connected a spring and dash-pot mechanism S, which is shown conventionally. This mechanism S is of the usual well-known construction, and acts to move the switch points to the normal or main-track position, and hold them there, in a manner familiar to those skilled in the art. A hand-throw device or switch stand HT, of the usual construction, is connected to the mechanism S, and enables the switch 3 points to be shifted from the normal or maintrack position to the reverse position for train movements into and out of the passing siding PS, the switch points being locked in this reverse position by the hand-throw device HT l in the usual way.

Considering the lock for the spring switch SlV, constituting an important part of the system of this invention, a lock rod LR is connected to the front rod 7 of the switch ll SW in the usual way, indicated by dotted lines, and is provided with a hole to receive a lock bolt or plunger LP, when the switch points are in the normal position as shown.

A suitable casing, not shown, supports and A shaft- 14, indicated by a dotted line, is connccted to the lock plate 12 and operates circuit controller cams and 16, having insulated projections which co-operate with pairs of contact fingers 17, 18, 19, and 20, so as to open or close these contact fingers in diftercnt positions of the shaft, in the manner explained hereinafter. The lock plate 12 is formed with a notch or shoulder 12 for cooperating with a pivoted lock dog 21 adapted to drop by its own weight (aided by a spring if desired) into position to engage said shoulder 12 A lock magnet L, is arranged so that, when energized, it lifts the lock dog 21 out of engagement with the shoulder 12 and trees the lock plate 12.

In the arrangement shown in Fig. 1, which may be modified as later described, a stick relay LS and an emergency release push button ER, with tl e associated control circuits, are employed for the control of the lock mag net L. These various parts of the lock are supported and housed in a suitable casing, as shown in said patent to J. E. Stephenson; and the door (not shown) for this casing, giving access to the handle 13, is provided with the usual hasp and padlock and is also formed with a recess or projecting lugs, as shown in said Stephenson patent, so that the door cannot be closed and locked unless the handle 13 is in one or the other of two positions shown in Figs. 1 and 3.

This invention contemplates utilizing some suitable type of communication or supervisory control system by which the dispatcher or operator at the distant control otlice may energize or de-energize function control relays at the several switch locations or way stations. The communication system shown, for the purpose of illustration and explanation, comprises suitable manually operable control levers GLIV. GLE, and IL in the control otlice. indicated by the rectangle or dash lines designated CO, and function con trol relays IV, GIV, and GE, operatively connected to these control levers, so that the contacts of these relays may be positioned in accordance with the change in the position of the control levers. This operative connection may be obtained by a communication sys tem of the synchronous channel circuit type, such as shown and described for example, in the applicat on of R. C. Leake, et al., Ser. No. 335.740. filed August 14, 1929 or by a communication system of he duplex coded type such as disclosed for example in the application of N. D. Preston, et al., Ser. No. 455.304, led May 24, 1930. In tl e simplified arrangement illustrated, the relays W, G1, and

are of the polar type and are directly energzed over line wires 22. and 2ft with current or" one polarity or the other, in accordance with the position of the correspondleyer, which has its contacts connected to the opposite terminals of a battery having a mid-tap or neutral point connected to a common return wire designated as C.

This communication system also preferably includes means for indicating at the cont-rol otlice CO when the detector track section 4 is occupied. In the simplified arrangement shown for the purposes of explanation, this track circuit indication, commonly known as the OS indication, is obtained by reversing at the trout and back contacts 26 of the detector track relay 4T, the polarity of a line circuit including a line wire and a common return wire, so as to shift the polar contact 27 of a polar relay OS to light or extinguish a lamp 28, according to whether the detector track circuit is occupied or unoccupied. This OS indication may be obtained in other ways, and without the use of a special line wire, as shown in the applications of R. C. Leake, et al., Ser. No. 385,740, filed August 14, 1929, or N. D. Preston, et al, Ser. No. 455,304, filed May 24, 1930, above mentioned.

In the arrangement shown in Fig. 1,time locking means has been provided for the control of the relay 2LS-G governing the leavesiding signal 2LS, so as to afford special or additional protection for train movements oil of the siding. This time locking means may be omitted, if desired, and the operator relied upon to give the instructions to leave the siding by means of the signal indications or the telephone, in such a Way and at such time? that such train movement may be made safely. As shown, this time locking means comprises a stick relay GS and a time-element de} vice TE. The time-element device TE, as shown and described more in detail in the application of J. E. Willing, Ser. No. 463,903, filed June 26, 1930, is of the thermal element type, and comprises a bi-metallic member 30, which is biased to the right-hand position shown to close a pair of spring contact fingers 31. When a heating coil 32 on this member is supplied with electric current, the member is heated and gradually bent or deformed until, after the lapse of the predetermined time, such as one minute, it closes the normally open pair of spring contacts 33. The circuits of the relay GS and the time-element device TE, and the functioning of this time locking means are more conveniently explained in connection with the description of the operation.

Operation.-Having explained briefly the general organization of the system of this invention, its principles and mode of operation are best explained by describing the sequence of operations for some typical train movement (1) Assume that an east-bound train (traveling from left to right) is to go straight through on the main track by the passing siding PS. The operator positions the switch lever WL in the normal position shown, it not already in that position, and

the main track by the passing siding.

thereby energizes the relay V to shift its polar contact to the right-hand position shown. With the lock plunger LP in the hole of the lock rod LR, as shown in Fig. 1, the contacts 20 are closed, and the relay N is energized over a circuit from polar contact 35 of relay WV, wires 36, relay N, wire 3?, contacts 20 to The operator also shifts the signal lever GLE, governing east-bound train movement, from the stop position shown to the clear dotted line position, reversing the polarity of energization of the east-bound signal control relay GE, and thereby causing its polar contact 38 to shift to the right-hand dotted line position. The other signal lever GLV, governing west-bound train movements, being left in the stop position, the polar contact 39 of the west-bound signal control relay GlV is held in the left-hand position.

Under these conditions, and assuming no train present in the block protected by the approach signal 1, that is, within the control limits for the line relay 1H, the relay 1G may be energized to clear the signal 1 over a circuit from polar contact 39 of relay Gil wire 40, polar contact 38 of relay GE to the right, wire 41, front contact 42 of relay N, wire 43, front contact 4% of line relay 1H, wire 45, relay 1G, to

In this way, the operator can direct an eastbound train by the indication of the signal 1 to advance at normal running speeds oIn t should be noted that the relay N cannot be energized unless the contacts -20 are closed, and these contacts are not closed, unless the switch points are positively locked in the normal position. This makes it safe to operate an east-bound train at normal running speed in the facing direction over the switch SWV.

The operation of allowing a west-bound train on the main track to pass the switch SW is the same as for an east-bound train movement, except that the operator shifts the signal lever GLW, instead of the signal lever GLE, to the clear position, thereby positioning the polar contact 39 of the relay GV to the right to establish an energizing circuit for the relay 2G, to clear the signal 2, said circuit being from polar contact 39 of relay GVV to the right, wire 46, front contact 47 of relay N, wire 48, front contact 49 of line relay 2H, wire 50, relay 2G, to

(2) Assume now that the operator desires to have an east-bound train take the siding. To do this, the operator shifts the switch lever 7L to the reverse position, shown in dotted lines, thereby shifting polar contact 35 of relay V to the left, and energizing the relay R, and de-energizing the relay N at the same time.

WVith the signal lever GLE operated to the clear position for east-bound train movement, and with the relay N de-energized and the relay R energized, a circuit is established for energizing the relay lTSG, to clear the take-siding signal ITS as follows polar contact 39 of relay SGVV to the left, wire 40, polar contact 38 of the relay GE to the right, wire 41, back contact 42 of relay N, wire 51, front contact 52 of relay R, wire 53, relay lTSG to The signal 1 is held at stop, since the deenergization of the relay N opens the energizing circuit for the relay 1G. Vith the signal 1 indicating stop, the next signal (not shown) in the rear thereof for governing traffic in the same direction will indicate caution in the usual way, and the east-bound train in question will slow down and come to a stop at the signal 1. Noting that the take-siding signal indication is displayed, the train crew knows that they are supposed to take the siding. The trainman goes up to the switch, unlocks the case for the switch lock, and moves the handle 13, from the position shown in Fig. 1, counterclockwise to the position shown in Fig. 2, in which the upper end of the link 10 is beyond the dead-center and holds up the weight 11 and keeps the locking plunger LP disengaged from lock rod LR. The switch is now unlocked, and can be moved to the reverse position by hand-throw device HT, whereupon the trainman signals the train to ad- Vance.

When the switch is thus unlocked, the contacts 20 are opened, breaking the energizing circuit for the relay N, so that even if the operator should change his mind, or carelessly move the switch lever WL back to the normal position, the signal 1 could not clear, and give an improper indication to the train to advance on the main track, while the switch is unlocked.

After the east-bound train in question has passed over the switch into the siding, the switch has to be restored to its normal position by the hand-throw device HT and again locked. While the trainman must of course remain at the switch until after the train has passed, so as to restore the switch to the normal position by the hand-throw device HT, the switch lock may be so manipulated that it is automatically locked after the train has passed and the switch restored to the normal position. This self-restoring feature of the switch lock is particularly useful to avoid train delay in the case of a movement off of the siding, as presently to be explained; but this self-restoring feature may also be employed in the case of a train movement into the siding.

lVhen the handle 13 of the switch lock is thrown by the trainman to the full-unlocked position shown in Fig. 2, the contacts 17 are closed to establish a pick-up circuit for the stick relay LS from contacts 17, wires 57 and 58, relay LS to The relay LS is stuck up by a stick circuit from front contact 60 of the detector track relay 4T, wire 61, release button ER, wire 62, front contact 63 of relay LS, wires 64 and 58, relay LS to WVith the relay LS thus energized, the mag net L cannot be energized, its energizing circuit hereinafter traced being broken at the back contact 66 of the relay LS. Consequently, the handle 13 may be put by the trainman into the self-restoring position shown in Fig. 3, in which the upper end of the link is to the right of the dead-center position, and in which the locking plunger LP and the weight 11 are held up by the engagement of the lock dog 21 with the shoulder 12 of the plate 12. In this position, the contacts 17 are open, so that the relay LS may be de-energized by opening its stick circuit; and the contacts 18 are closed, so that the magnet L may be energized. After the trainman has put the handle 13 in this self-restoring position shown in Fig. 3, he may close and lock the door of the casing for the switch lock; and

the switch lock Will be automatically locked without further attention on his part in the following way.

When the east-bound train in question enters the detector track section 4: and opens the front contact of the track relay AT, the

stick relay LS is de-energized; and when the rear end of this train has cleared this detector track section, an energizing circuit for the magnet L is established from front contact 60 of track relay 4T, wires 61 and 65,

3 provided, so that the magnet L may be deenergized to release the lock plate 12 and permit the dropping of the lock plunger LP to the locked position, in case the switch has been unlocked by mistake, or for any other reason, and is to be locked up again, without a. movement of a train into the detector track section. It can be readily understood that operation of the emergency release button ER breaks the stick circuit for the relay LS and permits energization of the magnet L over the circuit above traced. It can also be readily understood that, if the trainman should fail to move the handle 13 over to the full-unlocked position shown in Fig. 2,

so as to close the contact 17 and energize the relay LS, the magnet L would at once be deenergized as soon as the handle was re turned to the self-restoring position shown in Fig. 3, and the switch would again be automatically locked, unless it has been moved out of the normal position by the hand-throw device HT. Consequently, in the ordinary manipulation, the trainman is automatically required to throw the handle 13 to the full unlocked position (shown in Fig. 2) so as to energize the relay LS, before he can put the handle 13 in the self-restoring position and still have the switch remain unlocked, (shown in Fig. 3), then close and lock the door of the switch lock, and proceed to the hand-throw device HT.

After the train has entered the siding, and the switch has been restored to the normal position and locked, the operator may direct the trains to move over the switch in either direction on the main track, as above described.

Assume now that the operator desires to let out a west-bound train standing on the siding PS. To do this, he puts the switchlever WL in the reverse position and the signal lever GLVV in the clear position. This establishes a circuit for energizing the takesiding indicator LS1 from polar contact 39 of relay G? to 'the right, wire a6, back contact 47 of relay N, wire 70, front contact 71 of relay R, wires 72 and 73, indicator LSI to This advises the train crew that the operator desires them to move out of the sidmg.

. In lieu of the indicator LS1, the operator may communicate the same instructions to leave the siding to the train crew over the telephone. Such a telephone is located at each siding end, or corresponding track location, in accordance with the common practice in centralized traflic control systems; and the conductor of a train held at such a point by y the signals is required to call up the operator, who may then give the necessary instructions. For example, the crew of a train standing on the siding may be instructed to come out after the next east-bound train has passed.

The movement of a train from ofl? of the siding in the case assumed requires trailing of the points of the switch SW, and the switch lock must be released by the trainman as above described, before the train passes over the switch, otherwise the switch points could not be trailed without breaking or damaging the switch lock. To unlock the switch SW for such a trailing movement oif of the siding, the trainman manipulates the handle 13 in the same way above described, first to the full unlocked position shown in Fig. 2, to pick up the relay LS, and then to the selfrestoring position shown in Fig. 3. Disregarding for the present the operation of the time locking means, and assuming the relay GS to be energized and the contacts 31 of the time-element device TE to be closed, then after such unlocking operation of the switch, a circuit for energizing the relay 2LSG to clear the leave siding 2LS is established from polar contact 39 of relay GW to the ioo its

izo

right, wire e6, back contact 47 of relay N, wire 7 0, front contact 71 of the relay R, wires 72 and 74, contacts 31 of the device TE, wire 75, front contact 76 of relay GS, wire 77, front contact 78 of the line relay 2H, wire 79, front contact 80 of relay LS, wire 81, contacts 19, wire 82, relay 2LSG, to

This clearing of the leave-siding signal 2LS shows that the switch SIV is unlocked (contacts 19 being closed), and may be properly trailed, and that there is no opposing train approaching (the line relay 2H being energized and its front contact 78 being closed). The west-bound train on the siding may therefore safely pass out into the main track in obedience to the clearing of the signal 2LS.

hen this west-bound train in question advances from the siding into the detector track section 4, first the relay LS is de-energized; and then after the train has cleared this detector track section, the magnet L is energized to restore the lock to the normal position as shown in Fig. 1, in the same way asabove explained. The switch points are forced over to the reverse positions by the wheels of the train as it trails through the points, and are then returned to the normal'position by the spring mechanism S after the train has cleared the switch.

From the foregoing it can be seen that the operator may easily and efficiently direct train movements over the spring switch SW into and out of the passing siding, and in either direction on the main track. For an east-bound train movement in the facing direction on the main track, the home signal 1 may clear, provided the switch is locked; and consequently such train movements in the facing direction may be safely made at normal speeds.

When the switch is unlocked, either in order that it may be reversed for an east-bound train movement into the siding, or in order that it may be trailed by a west-bound train coming out of the siding, the trainman by easy manipulation is able to leave the switch lock in such a condition that it will be automatically restored to the locked condition as soon as the train has passed, and the switch points are in the full-normal position. In the case of a train movement off of the siding, this permits the trainman to condition the switch for a trailing movement, and then return and board his train, thereby avoiding stopping of the train, after it has passed over the switch, in order that the trainma-n may restore the points and climb aboard, as is the case with the ordinary hand-thrown switch. This materially facilitates the movement of trains and makes it possible to handle trafiic more expeditiously, with the system of this of course wait until the train has passed, be fore restoring the switch to the normal position by the hand-throw switch I-IT, but in this case, the train taking the siding will ordinarily stop, so that there is no delay.

Considering now the time locking means, it will be evident after a little consideration that, if a westbound train on the main track is approaching the switch SW at speed, another trainshould not come out of the passing siding PS. Vhile provisions (not shown) may be made for putting at stop the approach signal next in the rear of the signal 2 and governing west-bound traific in the same direction, as soon as the switch is unlocked, and before the leave-siding signal 2LS can be cleared, this does not provide complete pro tection, since the west-bound train on the main track may pass this approach signal before the switch is unlocked and may reach the switch, travelling at high speed under a proceed signal, at about the time the train pulls off of the siding, with the result that an unavoidable collision may occur. For these and other reasons, it is preferred to employ a time locking means which prevents clearing of the leave-siding signal 2LS until a predetermined time interval, such as two minutes, has elapsed after the signal 2 has been put to stop, once it has been cleared. In other words, before the leave-siding signal 2LS can be cleared, the signal 2 must have been at stop for at least two minutes, so that any west-bound approaching train will either have had time to pass over the switch, or else will have received a caution indication at the approach signal in the rear of the signal 2 and will have come to a stop at the signal 2.

Assuming the parts of the time locking means to be in the normal position, as shown, when the relay 2G is energized to clear the signal 2, it breaks at its back contact a stick circuit for the relay GS which may be traced from back contact 85 of relay 2G, wire 86, front contact 87 of relay GS, wires 88 and 89, relay GS, to This deenergization of the relay GS opens at its front contact 76 the energizing circuit for the relay 2LSG above traced, so that the leavesiding signal 2LS cannot be cleared.

WVhen the relay 2G is subsequently de-energized to put to stop the signal 2, the heating 'coil 32 is energized over a circuit from back contact 90 of relay GS, wire 91,v

heating coil 32, wire 92, back contact 93 of relay 2G, to After a predetermined time interval, approximately half of the total time desired, the member 30 closes the contacts 33 and establishes a pick-up circuit for the relay GS, which may be readily traced on the drawing. As soon as the relay GS picks up, it is stuck up through its stick circuit, and'at the same time breaks at its back contact 90 the circuit for the heating coil 32. The'energizing circuit for the relay QLSG is now closed at the front contact 76 of the relay GS, but is opened at the contact finger 31. After another predetermined time interval, the thermal member is cooled sufficient-ly to assume its normal biased position and close the contact fingers 31, whereupon the relays QLSG may be energized to clear the signal QLS.

This time locking means, utilizing a thermal element and requiring the over-and-back movement of the thermal member 30, while preferably used as a part of the complete system of this invention, is also disclosed and claimed in my prior application, Ser. :10.

463,940, filed June 26, 1930.

One of the problems in connection with an automatically restored lock for spring switches relates to the control of the magnet L, so that this magnet may be properly energized to permit automatic restoring of the lock; and Figs. l, 5, and 6 show modified arrangements for controlling the magnet L which may be used instead of the particular arrangement shown in Fig. 1.

Referring to the modification of Fig. 4, the energizing circuit for the magnet L includes a back contact of stick relay LS, wire 96, front contact 9? of the detector track relay elT, wire 98, contacts 18 and wire 99, substantially the same as Fig. 1. The relay LS is picked up directly by a push button OB, through a circuit readily traced in the drawing, and is stuck up through the front contact 60 of a track relay 4T and an emergency release button Ell, substantially the same as in Fig. 1. The operation of this modification will be apparent from the foregoing explanation of the arrangement shown in Fig. 1, the only diiference being that the relay LS is energized by an operating push button OB, instead of by the contacts 1'? closed by movement of the handle 13.

Referring to the modification of Fig. 5, the energizing circuit for the magnet L is from back contact of track relay 3T, wire 101, magnet L, wire 102, contacts 18, wire 103, front contact 104 of track relay LT. In this modified arrangement, a train leaving the siding opens the front contact 104 of the track relay IT, and the magnet L is not energized until this train has cleared the detector track circuit. For a train entering the siding, and presumably standing on the track section 3 ano closing the back contact 100 of the track relay 3T,

the trainman will have to move the switch Sil to the reverse position by the handtl ow device HT, before shifting the handle 13 to the self-restoring position shown in Fig.

- 3, so that although the magnet L. is energized and the weight 11 released, the locking plunger LP rests on the lock rod LR, and cannot drop to the locking position, until the switch SW is restored to the normal position by the hand-throw device HT.

In the modification of Fig. 6, the energizing circuit for the magnet L is from through the back contact 105 of the remotely controlled relay R, wire 106, front contact 107 of the track relay 4T, wire 108, contacts 18, wire 109, magnet L, to In this arrangement, the magnet L is energized to restore the switch look by the distant operator or dispatcher. In the case of an eastbound train movement into the siding, the switch is reversed by the hand-throw device HT, before the switch lock is placed in its self-restoring position, the same as in the case of the modification of Fig. 5. For a trailing train movement off of the siding, the

relay It is energized, as above explained, to clear the leave-siding signal 2L8, and hence the magnet L is maintained de-energized when the switch lock is put by the trainman into the self-restoring position of Fig. 3. When this west-bound train in question passes from the siding into the detector track circuit, an OS indication is displayed before the operator in the control ofiice as above eX- plained, and he may then throw the switch lever W L to the normal position, de-energizing the relay R and closing its back contact 105, so that when the train has cleared the detector track circuit, the magnet L is energized, and the switch lock automatically restored. The operator need not shift the switch lever WL at once, but may wait until a train movement over the switch in the normal position is desired, whereupon the magnet L is energized and the lock automatically restored.

lVhat I claim is 1. In a traflic controlling system for railroads, the combination with a spring switch at the end of a passing siding, of a manually releasable lock for holding said switch in the normal position, a'signal governing tralfic from said siding over said switch in the reverse position and in a switch trailing direction, remote controlled means for governing the indications of said signal, and means for preventing the clearing of said signal while said lock is effective.

2. In a traific controlling svstem for railroads, the combination with a spring switch at the end of a passing siding, a manually releasable lock for holding said switch in its normal position, a signal governing traffic over said switch on the main track, means preventing the clearing of said signal unless said lock is effective, a leave-siding signal governing traffic from the siding over said switch in the reverse position, means for preventing clearing of said leave-siding signal unless said lock is released, and manually controllable means for governing said signals selectively from a distant point.

3. Ina traffic controlling system for railroads, the combination with a spring switch at the end of a passing siding, of a manually trafiic over said switch in the facing direction, means for preventing clearing of said signal unless said lock is effective, a takesiding signal directing trains to take the siding and in a switch facing point direction,

' and manually controllable means for governing said signals selectively.

l. In a system of the type described, a spring switch at the end of a passing siding, a lock for holding said switch in the normal position for train movements on the main track, a leave-siding signal, means preventing the clearing of said signal unless said lock is released, a leave-siding indicator operable independently of the condition of said lock, and remote controlled means for governing said signals.

5. In a system for governing traffic on railroads, the combination with a spring switch at the end of a passing siding, a lock for holding said switch in its normal position for train movements on the main track, a hand-throw device operable to shift said switch to its reverse position when unlocked, signals governing traffic in opposite directions over said switch in its normal position, means preventing the clearing of said signals unless said lock is effective, a leavesiding signal governing traflic oil of the siding over said switch in its reverse position, means preventing the clearing of said leave-siding signal unless said lock is released, a takesiding signal indicating that a train approaching the switch in the facing direction should take the siding, and manually controllable means for governing said signals selectively from a distant point.

6. In a system of traiiic control for railroads, the combination with track switches at the ends of a passing siding, spring means tending to move and hold each switch in the normal position for train movements on the main track, a manually releasable lock for holding each switch. in its normal position, a hand-throw device for shifting each switch to its reverse position if unlocked, signals governing traiiic in opposite directions over each switch in the normal position, means preventing the clearing of said signals unless the corresponding lock is effective, a leave-siding signal governing train movement from the siding over each switch in its reverse position, means preventing the clearing of each leave-siding signal unless the corresponding lock is released, a take-siding signal at each end of the siding indicating that an approaching train should tal: the siding, and manually controllable means for governing said signals selectively from a distant point.

7. In a traffic controlling system for railroads, the combination with a track switch, spring means tending to move and hold said switch in its normal position, a lock biased to a locking position to hold said switch in its spring-pressed position, a signal governing train movement over said switch in its other position, a line relay controlled by track circuits in advance of said signal, a remote controlled relay, a circuit controller closed only when said lock is in its released position, and a circuit for clearing said signal governed by said remote controlled relay and including said circuit controller and a front contact of said line relay.

8. In a system of the character described, the combination with a spring switch at the end of a passing siding, a lock for holding said switch in its normal position, a leavesiding signal governing train movements from said siding over said switch in its reverse position, means preventing clearing of said leave-siding signal unless said lock is released, a signal governing train movements over said switch in the normal position in the trailing direction, and time locking means for preventing clearing of said leave-siding signal independently of the condition of said lock until said other signal has indicated stop for a predetermined time.

9. In a traflic controlling system for railroads, the combination with a track switch at the end of a passing siding, spring means tending to move and hold said switch in its normal position for train movements on the main track, a lock for holding said switch in its normal position, a signal governing train movement from the siding over said switch in its reverse position, a line relay controlled by track circuits in advance of said signal for causing said signal to inclicate stop when a train is present on said track circuits, means for preventing clearing of said signal unless said lock is released, a second signal governing traffic in the same direction over said switch in the normal position, time locking means for preventing clearing of said first signal until said second signal has indicated stop for a predetermined time, and manually controllable means for governing said signals from a distant point.

10. In a system of the type described, the combination with a track switch at the end of a passing siding, spring means tending to move and hold said switch in its normal position for train movements on the main track, a leave-siding signal governing train movement from said siding over said switch, a second signal governing train movement over said switch in its normal position in the same trailing direction, and time locking means for preventing the clearing of said leavesiding signal until said second signal has indicated stop for a predetermined time.

11. In a system for governing railroad traffic, the combination with a track switch,

governing train movement in the same direction over said switch in its reverse position, means preventing clearing of said second signal unless said lock is released, and time locking means preventing the clearing of said second signal independently of the condition of said lock until after said first signal has indicated stop for a predetermined time.

12. in a system of control for spring switches, the combination with the movable switch points of a track switch, spring means tending to move and hold said switch points in the normal position for train movements on the main track, a lock for holding said switch points in the normal position and biased to the locking position and releasable manually, a lock magnet for holding said lock in its released position, means conditioned by movement of said lock to its releasing position for governing said lock magnet to release the lock after a train has entered and left said detector track circuit.

13. In a system of control for spring switches, the combination with the movable switch points of a track switch, spring means tendin to move and hold said switch points in the normal position for train movements on the main track, a lock for holding said switch points in the normal position and releasable manually, a lock magnet for holding said lock in its r leased position, a detector track circuit adjacent said switch, and means rendered efiective after movement of said lock to its released position for energizing said lock magnet when a train enters and passes out of said detector track circuit.

14-. In a system of control for spring witches, the combination with the movable switch points of a track switch, spring means tending to move and hold said switch points in the normal position for train movements on the main track, a lock for holding said switch points the normal position and biased to the locking position and releasable manually, a lock magnet for holding said lock in its released position, a detector track circuit adjacent said switch, a stick relay controlled by said track circuit, and an energizing circuit for said lock magnet controlled by said stick relay ant also by said track circuit.

15. In a system of control for spring switches, the combination with the movable switch points of a track switch, spring means tending to move and hold said switch points in the normal position for train movements on the main track, a lock for holding said switch points in the normal position and biased to the locking position and releasable manually, a lock magnet for holding said lock in its released position, a detector track circuit adjacent said switch, a stick relay energized by movement of said lock to its released. position, a stick circuit for said relay including a front contact of the track relay or said detectortrack circuit, and an energizing circuit for said lock magnet including a back co: ct of said stick relay and a front contact of said track relay.

in a system of the type described, the combination with a spring switch, a lock for holding said switch in the normal position and biased to its locking position and re leasahle manually, a lock magnet for holding said lock in its released position, a detector track circuit, and an energizing circuit for sold loci: magnet including in series a front. contact or" the track relay of said detector track circuit and a back contact of the track relay said adjacent track circuit.

17. In a system of the type described, the combination with a spring switch, a. lock for holding said switch in the normal position and biased to its lookin position and releasable manually, a 1 ch magnet for holding said lock i its released position, a detector rack circuit adjacent the Switch and remote control means for energizing said lock magnet only it said detector track circuit is not occupied.

18. in a system of he type described, a spr' switch at the end of a passing siding,

lock for holding said switch in the normal posit-ion for train movements on the main track, a leave-siding signal, means preventthe clearing of said signal unless said lock is released, a leave-siding indicator operalole when the loci: is released, and remote controlled means for governing said signals.

19. in a trathc controlling system for railroa s, the combination with av spring switch at the end of oassin sidin of a manuall releasable lock for holding said switch in the normal position, a s1gnal' governing traiiic from said sidlng over said switch in the rev e position and in a trailing direction, 1 ar or preventing the clearing of said o said lock is effective.

em of the type described, in combination. w ith a spring switch, a lock for i 'd switch in the normal position to its locking position and releas 1111:], a lock magnet for holding its released position, a detector aclr circuit adjacent the switch, and manually operable switch means in the energizing circuit of the lock magnet.

21. in system of the type described, in combi ation with a spring switch, a lock for holding said switch in the normal position and biased to its locking position and releasable manually, a loci: magnet for holding said lock in its released position, a, detector track circuit adjacent the switch, and manually operable switch means in the energizing circuit of the lock magnet, effective to energize the lock magnetonly if the detector track circuit is unoccupied.

In testimony hereef I aflix my signature.-

ROBERT M. PHINNEY.- 

